Triangular body-cover model of the vocal folds with coordinated activation of the five intrinsic laryngeal muscles

Abstract

Poor laryngeal muscle coordination that results in abnormal glottal posturing is believed to be a primary etiologic factor in common voice disorders such as non-phonotraumatic vocal hyperfunction. Abnormal activity of antagonistic laryngeal muscles is hypothesized to play a key role in the alteration of normal vocal fold biomechanics that results in the dysphonia associated with such disorders. Current low-order models of the vocal folds are unsatisfactory to test this hypothesis since they do not capture the co-contraction of antagonist laryngeal muscle pairs. To address this limitation, a self-sustained triangular body-cover model with full intrinsic muscle control is introduced. The proposed scheme shows good agreement with prior studies using finite element models, excised larynges, and clinical studies in sustained and time-varying vocal gestures. Simulations of vocal fold posturing obtained with distinct antagonistic muscle activation yield clear differences in kinematic, aerodynamic, and acoustic measures. The proposed tool is deemed sufficiently accurate and flexible for future comprehensive investigations of non-phonotraumatic vocal hyperfunction and other laryngeal motor control disorders.

LaDIVA: A neurocomputational model providing laryngeal motor control for speech acquisition and production

“…Moreover, due to the large number of defined biomechanical control parameters, LaDIVA possesses the ability to carry out subject-specific simulations. This feature is inherited to LaDIVA from the extended BCM, which has been successfully used to conduct subject-specific modeling in individuals with vocal hyperfunction [ 14 , 96 ]. Although simulating subject-specific data is out of scope for the current investigation, this is a potential area of future expansion of LaDIVA.…”

Asymmetric triangular body-cover model of the VFs with bilateral intrinsic muscle activation

“…The Triangular Body-Cover Model (TBCM) (Alzamendi et al ., 2022; Galindo et al ., 2017), a symmetrical low-order model of the VFs, serves as the foundation for our asymmetric triangular body-cover model (a-TBCM). The TBCM incorporates tissue-fluid-acoustic interactions at the glottis, enabling simulations of sustained vowels and time-varying glottal gestures.…”

“…The activation levels of the primary adductors (LCA and IA muscles) were combined by setting a LCA = a IA , streamlining the adjustable variables for sustained VF oscillations. Additionally, the PCA activation ( a PCA ) was consistently set to zero across all simulations, neutralizing its significant abductor effect on glottal posture (Alzamendi et al ., 2022). For the TA and CT muscles, activations a TA and a CT were calibrated to produce voiced sounds within the fundamental frequency range of 90 to 100 Hz, aligning with the physiological characteristics of a male modal voice.…”

“…For the TA and CT muscles, activations a TA and a CT were calibrated to produce voiced sounds within the fundamental frequency range of 90 to 100 Hz, aligning with the physiological characteristics of a male modal voice. The activation levels were determined based on muscle activation plots reported in Alzamendi et al . (2022).…”

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FIG. 8: (Color online) Top view: 2D diagram describing the abducted VFs positioning for the cover blocks in the a-TBCM.

Thereupon, empirical rules are applied for adjusting the geometrical and biomechanical parameters (Alzamendi et al ., 2022; Titze and Story, 2002) (e.g., thickness, depth, and mass m for each block, the nodal point, the glottal convergence, and the values for the spring k and damping d parameters (see Figure 1)) of the left/right TBCM.…”